/Engine/Source/Developer/TreeMap/Public/STreeMap.h
Finds the node visual that's under the cursor
[FTreeMapNodeVisualInfo](API\Developer\TreeMap\FTreeMapNodeVisualInfo) * FindNodeVisualUnderCursor ( const [FGeometry](API\Runtime\SlateCore\Layout\FGeometry) & MyGeometry, const FVector2D & ScreenSpaceCursorPosition )